I have quite a few Sony Walkman DAPs but two of them I own which were both bought in the UK have different volumes. The DAPs in question are my Sony S639f and Sony A845. The volume at 20/30 on my S639f is equivalent to the maximum volume of 30/30 on my A845. I then set both DAPs into test mode and came to a startling discovery. On SPSET on the S639f it is set at EU (SPS:OFF) yet on the A845 it is set at CEW (SPS:ON) which explains why my S639f sounds louder than my A845. Does anyone know what CEW stands for?

Anyway it looks like Sony have got worse with their volume capping on new European Sony Walkmans.

Absolutely nothing. There is no way of adjusting anything on the test mode as everything is locked I doubt I will be buying anymore Sony DAPs now since the EU volume restriciton has become more strict which is a shame because I really liked the sound quality of the Sony DAPs. Oh well!!

* France has limited audio output to 100dB for a very long time for mp3 players (started in 2002 with the iPod was launched in France).

* In other EU countries, there is no such law so far, although a lot of EU players have been capped similarly to French requirements recently (probably easier to manufacture since they only have to release one model for all of Europe this way).

* In 2009, the EU discussed about setting up a volume cap at 80dB (which is not that loud, I admit) based on clinical studies, but it was finally not applied.
Instead it was suggested to only implement this as a "soft" cap, meaning a simple software setting that you can deactivate. By the way, 2010 American scientific studies confirmed the European ones, stating that music levels above 85dB (with peaks at 100dB) were causing significant ear damage, but so far nothing has come out in the US to enforce volume restriction.

The only thing which is not mentioned anywhere (and makes the whole thing not clear, or "stupid" as many people comment) is what kind of device they use to measure sound and set up these limits, because the endresults will vary a lot depending on the impedance of users' headphones.

By the way, Sony had already implemented this kind of "soft cap" a long time ago under the name AVLS (Automatic Volume Limiter System), it was already present on Sony's portable CD-players in the 90's. It is also present in the NWZ-A84x, and limits max volume to 20/30 instead of 30/30 (not so "automatic" anymore ).

On the European A84x series, volume seems to be capped a bit more than usual, a lot of people complain about that.

But I don't think the A84x series is so badly capped, I find it loud enough with all my headphones, including the AKG K240, which is quite hard to drive (although not as much as the K701). With really low impedance IEMs like Shure SRH840 or Philips SHE9850, I can't even reach 20/30 volume on my A847.

A cheap amp (FiiO E7 or E11) will increase the max volume comfortably if you ever need it.
I tend to use the E7 with the AKG K240 when the source material has really low level recording, and this combo can be very loud.